About two weeks ago it was
announced that a U.S. grad student, Clay Moulton, won second place in a "Greener Gadgets Conference" competition for inventing a floor lamp powered by gravity.
The
concept was that a person would place a weight (about ten pounds) at the top of a four-foot column. Over the course of the next four hours, the weight would descend down the column, causing a rotor to spin that would produce a gentle light (about the strength of a 40 watt bulb).
Moulton's concept generated a lot of interest on blogs, but also a lot of skepticism. People who crunched the numbers insisted the thing could never work. It was outputting way more energy than was being put into it. But it seemed as if Moulton had actually built a prototype, and it did work -- and he had won an award for it. So the skeptics were kept at bay.
The skeptics were right. The thing would never work. Moulton has
now admitted he hadn't built a prototype. It was just pie-in-the-sky theorizing. It would only work if super-efficient LEDs were invented at some point in the future. Or if you used a ten-ton weight. Moulton has offered to concede the second place prize.
The Gravity Lamp seems typical of so many of the inventions you read about that promise to save the world's energy problems. Somehow they never pan out. (via
core77.com)
Comments
I know it sounds nasty - but it shows that they only want to win, not put in the actual effort to get it RIGHT.
Though, I think that the judges didn't do a very good job if they didn't double check to make sure it wasn't a fake.
I do commend the guy for admitting his deception though.
m = 5 * 10lbs = 50 lbs = 22.67 kg
h = 58" = 1.4732 m
E = mgh = 22.67kg * 1.4732m * 9.8m/s2 = 327.294 J
With a 0% loss of energy 327 J lights up a 40w lightbulb for 8.18 seconds -or- over 4 hours you would be able to use a 0.0227 watt lightbulb.
A highschool physics student could have caught this as bogus.
This energy source is not new-- my granparents had a cuckoo clock that was powered by two weights (probably a pound or two each) hanging from the bottom of the clock on long chains. The weights were shaped like large pine cones. My Grandma would "wind" the clock by pulling the free ends of the chains to raise the weights, then they would lower themselves slowly and turn gears as they went down. This would power the clock for about a week, inlcuding the hands, a swinging pendulum, and bird jumping out and saying "woohoo" every quarter hour.
Ah, I miss my Grandma.
The weight and height the guy describes in the competetion describes is just not enough to power a light bulb.
The reality is that LEDs are already pretty efficient at converting electricity into light anyway and the improvements likely in the future are probably going to be only marginal and certainly will not increase it to more than 100%.
http://www.vtnews.vt.edu/story.php?relyear=2008&itemno=111
I don't think that even with a 100% efficient light source you could get this to work.
Consider that an ideal white light source for the human eye has an efficiency of 240 lumens/watt (http://en.wikipedia.org/wiki/Incandescent_light_bulb)
A 40 watt incandesent light produces 500 lu of light. Therefore a 100% efficient light source would require 2.08 watts of power.
Using the above 327 J (327 watts), you'd have a runtime of 157 seconds, somewhat less than 3 minutes.
And this guy is applying for a patent on converting potential energy to kinetic energy? It'll be interesting to see if the parent office awards it...
-lee